Biomaterial Database

The role of sulfhydryl groups in thyrotropin binding and adenylate cyclase activities of thyroid plasma membranes. 1979

Y Ozawa, and I J Chopra, and D H Solomon, and F Smith

The effects of sulfhydryl (SH) reagents on the binding of TSH to thyroid membranes and on membrane adenylate cyclase activity were studied. Diamide, a SH-oxidizing agent, enhanced [125I]iodo-TSH binding to thyroid membranes in a dose-dependent manner. On the contrary, dithiothreitol (DTT), a disulfide-reducing reagent, markedly inhibited this activity in a dose-dependent manner. These effects could not be attributed to a direct interaction between the reagents and the radioactive TSH. Scatchard plot analysis of the data was limited by curvilinear plots but suggested that diamide increases while DTT decreases the affinity of the receptors for TSH in thyroid membranes, neither reagent appeared to influence the capacity of TSH binding by membranes. The effects of diamide and DTT on adenylate cyclase activity of thyroid plasma membranes were just the opposite of their effects on TSH binding. Thus, diamide inhibited adenylate cyclase activity of thyroid plasma membranes while DTT increased basal enzyme activity and slightly but not significantly increased TSH-stimulated enzyme activity. The data suggest a possible physiological role for SH and disulfide groups of thyroid membranes in modulation of thyroidal activity.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003958	Diamide	A sulfhydryl reagent which oxidizes sulfhydryl groups to the disulfide form. It is a radiation-sensitizing agent of anoxic bacterial and mammalian cells.	Diazodicarboxylic Acid Bis(N,N-dimethyl)amide,Diazodicarboxylic Acid Bisdimethylamide,Dizene Dicarboxylic Acid Bis(N,N-dimethylamide),Dizenedicarboxylic Acid Bis(N,N-dimethylamide),Tetramethylazoformamide,Acid Bisdimethylamide, Diazodicarboxylic,Bisdimethylamide, Diazodicarboxylic Acid
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013438	Sulfhydryl Compounds	Compounds containing the -SH radical.	Mercaptan,Mercapto Compounds,Sulfhydryl Compound,Thiol,Thiols,Mercaptans,Compound, Sulfhydryl,Compounds, Mercapto,Compounds, Sulfhydryl